7083040 Tensioner as for a Belt Cleaner

8/4/2019 7083040 Tensioner as for a Belt Cleaner

http://slidepdf.com/reader/full/7083040-tensioner-as-for-a-belt-cleaner 1/43



US 7,083,040 B2

OTHER PUBLICATIONS

ASGCO, Installation Operation & Maintenance Manual, ,

ASGCO Manufacturing, Inc., Allentown, PA, 8 Pages.

Martin Engineering, Martin Piglet, Belt Cleaner and

Tensioners Operator's Manual, 1999, 30 Pages.McMastcr-Carr, Clamping Knobs, pp. 1864 and 1865.

ARCH Gordon Saber Belt Cleaners, Secondary Conveyor

Belt Cleaner and Mini Saber, http://www.archenv.comiprod-ucts/belt_cleaners/ ..., 1999,4 Pages.

ARCH Gordon Saber Primary Conveyor Belt Cleaner [EN],

Mini Saber and Saber, www.aeec.comiproducts/belt_cleaners/ ..., 2001, 6 Pages.

Martin Engineering, Piglet Pre-Cleaner and SecondaryCleaner, http://www.martin-ent.comicgi-binlentropy.cgi?$template-cgi ..., 2000, 2 Pages.Martin Engineering, Technical Data Sheet L3370-08-12/97,Piglet Belt Cleaners, 1997, 2 Pages.

Martin Engineering, Piglet Pre-Cleaner and SecondaryCleaner, http://www.martin-ent.comicgi-binlentropy.cgi? ...,Date Unknown, 2 Pages.Baking Industry Sanitation Standards Committee, http:/bissc.org/baking.htm, 1998, 11 Pages.International Search Report, PCTIUSOI/09000, May 9,2001.

* cited by examiner

http://www.aeec.comiproducts/

http://www.martin-ent.comicgi-binlentropy.cgi/?




http://www.aeec.comiproducts/



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US 7,083,040 B21

TENSIONER, AS FOR A BELT CLEANER

This Application is a division of U.S. patent applicationSer. No. 09/808,657 filed Mar. 15, 2001 now U.S. Pat. No.6,948,609, which claims the benefit of U.S. ProvisionalApplication Ser. No. 60/191,554 filed Mar. 23, 2000, and ofU.S. Provisional Application Ser. No. 60/247,520 filed Nov.9,2000.

FIELD OF THE INVENTION

The present invention relates to a tensioner and, in par-ticular, to a torsional tensioner.

BACKGROUND OF THE INVENTION

Scraper-blade type belt cleaners as applied to light-dutybelt conveyance systems are usually composed of little morethan a piece of plastic sheet stock, typically polyethylene,that has been machined to have an angled edge. Themachined edge serves as a belt scraper when held in prox-imity to or against the belt, typically by simple bolted angles,

channels or other brackets, often in "one-of-a-kind" mount-ing arrangements. These belt cleaners are often located on aconveyor system near the location at which material is 25

discharged from the conveyor belt (i.e., near the head orsnub pulley). Since these belt cleaners rarely incorporate anytype of blade tensioning system, regular adjustment of themounting arrangement is required to maintain blade pressureagainst the belt for proper operation. Due to the difficulty in 30

removing and re-installing the blade assembly when thesemounting arrangements are used, sanitary cleaning opera-tions are limited as a practical matter to In-Place Cleaning(IPC) techniques.

These "one-of-a-kind" belt cleaners are often designed 35

specifically for particular existing equipment and are retrofitinto such existing equipment by plant maintenance person-

nel, however, some Original Equipment Manufacturers(OEMs) do provide inexpensive cleaners with their convey-ance systems that are likewise impractical for easy use. 40

Moreover, OEM process equipment manufacturers wil lsometimes use a device similar to a belt cleaner to removeproduct from process rollers or to aid in directing the productcarried by the conveyor (e.g., guide rails or flow directors)or in shaping the product (e.g., dough rounders)

Certain "few-of-a-kind" scraper blade type belt cleanersfound on OEM designed conveyance systems and relatedprocess equipment incorporate a simple compression springassembly or similar mechanism to permit tensioning of thescraper blade against the conveyor belt. These units are 50

typically difficult, if not impossible, to properly clean andsanitize, and normal adjustment of the spring tension oftenrequires special tools and skilled personnel. Further, smallhardware or other parts often used on such systems areloosed or disassembled for cleaning and can easily find their 55

way into the process stream. Due to the relative complexityof a spring assembly, such tensioned systems are seldomdesigned and retrofit to existing equipment by plant main-tenance personnel.

One commercially available belt scraper that is purport- 60

edly configured specifically for food grade applications isthe Piglet™ scraper, which is offered for both primary("Pre-Cleaner") and secondary ("Post-Cleaner") scraperconfigurations. Elements of the this scraper that are bothundesirable and unlike the present invention include:

an internal elastomeric tensioner and end-housing which,due to the inherent difficulty of disassembling and

2cleaning such an assembly and to the lack of adequateseals, presents a potentially serious microbiologicalhazard when used in food grade applications;

a tensioner system which is difficult to utilize in the fielddue to the need for hand-tool adjustment of the tensionand the limited life of the set-screw type fasteners usedto adjust the tension after each cleaning;

a removal and installation scheme that requires thescraper blade to be "slid" off the ends of the blade-holder, thus making regular disassembly and cleaningextremely difficult; and

a segmented blade in which contaminating materials andmoisture can easily become entrapped in spacesbetween the blade and blade holder, and betweenadjacent ones of the four-inch blade segments.

Further, another company offers a Saber® Belt Cleaner,which is not designed for sanitary/food grade applications,but is "upgraded" by offering a scraper blade fabricated fromfood-grade material. This system utilizes an incremental

20 tensioning system, called the "Twister 'Iensioner", and uti-lizes a polyurethane torsion element. The tensioning unit isnot a sanitary design and presents a potentially serious

microbiological hazard because static material and moisturecan accumulate between the Twister Tensioner and the bladeholder tube. In addition, cleaning and/or inspecting this beltcleaner requires complete disassembly which creates a dif-ficulty while exposing the processing line to loose hardwarethat can easily find its way into the product as foreign matter.

Finally, ASGCO Manufacturing offers a modified versionof the Mini-Skalper™ scraper which is "upgraded" forsanitary/food-grade applications by offering both a food-grade scraper blade and by changing the blade holder andcomponents of the Roto- Twist™ tensioner to stainless steelmaterials and construction.

Accordingly, there is a need for a belt scraping apparatusthat is suitable for use in food-grade and/or other sanitarycleaning operations, although its use is not limited thereto.

In addition, it would also be desirable that both the arrange-ment and materials thereof be suitable for use in a sanitaryoperation, including the arrangement and materials of thescraper blade, the blade holder, the blade tensioning mecha-nism and the system arrangement.

To this end, a tensioner includes an outer collar affixed toa housing, an inner collar affixed to a blade holder, and a

45 torsion spring coupled between the inner and outer collarsfor urging a blade toward a belt.

10

15

BRIEF DESCRIPTION OF THE DRAWING

65

The detailed description of the preferred embodiments ofthe present invention will be more easily and better under-stood when read in conjunction with the FIGURES of theDrawing which include:

FIG. 1 s an isometric schematic diagram of an exemplaryscraping system arrangement showing a head pulley and aconveyor belt, in accordance with the invention,

FIG. 2 is an enlarged isometric schematic diagram of thescraping system arrangement of FIG. 1 in accordance withthe invention,

FIG. 3 is a schematic diagram, including a partial section,showing the scraping system of FIG. 1 viewed lookingtoward the conveyor belt,

FIG. 4 is a cross-section schematic diagram showing thetensioning arrangement of the system of FIG. 1,

FIG. 5 is a top-view schematic diagram showing thetensioning arrangement of the system of FIG. 1, with thelocking handle removed for clarity,



5US 7,083,040 B2

6and, we believe, for the first time addresses and fulfills thespecific needs of food manufacturing and related industries.

The conveyor and scraping system 10 of the presentinvention is generally described in relation to FIGS. 1, 2 and3 in which FIG. 1 is an isometric schematic diagram of an 5

exemplary scraping system arrangement 10 showing a headpulley 14 and a conveyor belt 12, in accordance with theinvention, FIG. 2 is an enlarged isometric schematic dia-gram of the scraping system arrangement 10 of FIG. 1 inaccordance with the invention, FIG. 3 is a schematic dia- 10

gram, including a partial section, showing the scrapingsystem 10 of FIG. 1 viewed looking toward the conveyorbelt 12.

The general operation of a belt scraper and conveyorsystem 10 is well understood and is described in great detail,for example, in several earlier patents issued to George Mott ,et al., such as U.S. Pat. Nos. 5,992,614, 5,887,702 and6,152,290. The operation of the inventive be lt scraper sys-tem 10 in relation to a conveyor belt 12 moving in a direction13 over a primary driving or powered (head) pulley 14rotatable about axle 15 is generally similar to other scrapertype belt cleaners, however, the inventive scraping system

10 comprises a novel scraper blade assembly 100 includingnovel scraper blade 120 which mechanically dislodges mate-rial from the conveyor belt 12; a novel blade holder 110 that 25

supports and locates the scraper blade 120, and a noveladjustable tensioning system 200 that, among other func-tions, acts to force the tip or scraping edge 122 of scraperblade 120 against the conveyor belt 12.

Scraper blade 120 is mounted to blade holder 110 and isconstrained by key bar 11 4 to rotate with blade holder rod112 which is rotatably mounted to and is supported at eachend by holes 28 of mounting plates 20 that are normallyrigidly affixed to members of the frame 16 of a conveyorsystem. Mounting plates 20 are mounted to conveyor frame16 either by welding 21 or by fasteners (not shown) throughthe provided clearance holes 22, 24, which may be circular

24 or may be slotted 22 to allow positional adjustment.Typically, an optional bushing or bearing 30 may be dis-posed in the hole 28 in mounting plate 20 through whichblade holder rod 112 passes. On the tensioner 200 side of thesystem 100, mounting plate 20 includes a half-can housing250 that is rigidly affixed to the mounting plate 20 such asby welding, e.g., weld 254. The centerline CL of half-canhousing 250, which is preferably a section of a hollowcylinder, corresponds to the centerl ine CL of blade-holder110, i.e . the CL of rod 112. A clamp 260 releasably fixes theposition of outer collar or flange 230 with respect to half-canhousing 250. For example, outer collar 230 has a radially-located threaded hole 232, (most desirably a thru hole forsanitary purposes), that accepts a threaded stud 262 which ispart of position-adjustable tension-locking handle 260.Threaded stud 262 passes through the circumferential slot270 provided in half-can housing 250 as it engages threadedhole 232 on outer flange/collar 230, so as to clamp collar 230and half-can housing 250 when tightened.

A metallic helix-shaped torsion spring 210 serves as theprimary torsioning element for rotatably urging blade edgeor tip 122 of blade 120 to bear against belt 12. Torsion spring210 is rigidly affixed at respective ends 212, 214 to "inner"collar 220 and to "outer" collar 230, both of which areco-linearly located at one end of blade holder rod 112. Innercollar 220 is rigidly clamped or other wise attached to bladeholder rod 112 so as to rotate therewith. Outer collar 230 isnot directly affixed to blade holder 112, but is radiallyconstrained by circumferentially located half cylinderreferred to as "Half-Can Housing" 250 and by central

circular bore or clearance hole 234 through which bladeholder rod 112 passes. Half-can housing 250 is positionedover, i.e. above, tension spring 210 to a lso serve as a shie ldto block falling material from landing on spring 210 andcollars 220, 230. Preferably, half-can housing 250 is aboutone-half of a cylinder, but may be between about If 3 and 2 /3

of a cylinder.When the blade/blade holder assembly 120/100 is rotated

to where it is held against the belt 12 surface, proper rotationof tension-locking handle 260 in the aforementioned half-can housing 250 slot 270 acts to increase (or decrease) thetension in torsion spring 210, thereby increasing (or decreas-ing) the applied pressure of the blade 120 against conveyorbelt 12. Tension-locking handle 260 acts, when tightened, to

15 clamp outer collar 230 to half-can housing 250 at any of anessentially infinite number of set-able locations along slot270, thereby applying and maintaining a precisely appliedtension of torsion spring 210 to blade 120. This uniquearrangement allows for precision set-ability of the tension

20 (i.e. blade 120 pressure against belt 12), which is a crucialrequirement for the light-duty belt industry where expensivesoft covered belts 12 are rapidly destroyed by excessive

tension applied by belt cleaning systems that lack prec isetension set-ability.

Half-can housing 250 rigidly anchors the outer collar 230(via the tightening of the tension-locking handle 260) withrespect to mounting plates 20 and fixed conveyor frame 16.Half-can housing 250, which is disposed above torsionspring 210 and collars 220 and 230, uniquely enables both

30 the direct tensioning of blade 120 during spring 210 adjust-ment and acts as a protective cover to prevent accumulationof food and other contaminating materials in and aroundtensioning system (tensioner) 200.

Scraper blade 120 is unique in both geometry and in the35 means by which it can easily be attached to and removed

from blade holder 110. In the food manufacturing industry,for example, both regulatory and good manufacturing prac-

tices often mandate the regular cleaning and sanitation ofequipment and devices in and around the product zone, i.e.40 the regions in which food is processed. In certain industries

(e.g. , meat and poultry processing), the cleaning of devicesand equipment that comes into contact with food is per-formed at least once per work shift. Ease of disassembly andaccess for "In-place Cleaning" (IPC, i.e. c leaning of equip-

45 ment in the location where it is used) and "Cleaning Out-ofPlace" (COP, i.e. cleaning in a location other than where theequipment is used) cleaning operations are essential designfeatures of devices like belt cleaners. The novel "snap-on"blade 120 (actually a "snap-on/snap-off" blade) facilitates

50 rapid and easy installation and removal of the plastic blade120 from the metallic blade holder 110 while completelyeliminating loose hardware (such as detent pins, nuts andbolts) that could contaminate the food being processed. Inmany cases, installation and removal of blade 120 may be

55 accomplished without the need for hand tools.Snap-on/snap-off blade 120 is fabricated from any of a

variety of pliable elastomeric/plastic materials includingfood and non-food grade polyethylene, polyurethane,polypropylene, polyvinyl-chloride (PVC), PTFE (Tefion™),

60 nylon, oil-filled UHMW-PE (ultra-high molecular weightpolyethylene), Delrin®. Hytrel®, and other suitable mate-rials. The snap-on installation of blade 120 typically requireshand-force only and is achieved by elastically deforming(i.e., spreading) the "legs" 130 of blade 120 as they engage

65 blade holder rod 112 and key-bar 114. For each of thematerials of construction mentioned, the geometry of legs130 is modified, e.g. , in thickness and/or shape, to facil itate



7US 7,083,040 B2

8the snap-on feature, while consideration is also given toensure a service life of several thousand cycles.

Addit ionally, the close tolerance (circumferential) f it ofscraper blade 120 and blade holder rod 112 prevents thestatic accumulation of food or foreign materials at or in this 5

interface therebetween. This feature is enhanced by designby permitting a residual elastic (clamping) force to remain inlegs 130 of blade 120 as they reach their fully-engagedposition on blade holder rod 112. Another novel and inherentattribute of blade legs 130 is their ability to function as 10

"skirts", enhancing the shedding of material from the sidesof blade 120 while impeding material build-up on bladeholder 110. Longitudinal motion of blade 120 along bladeholder 110 isrestricted by a radially oriented extending fixedpin 116 (or similar feature) affixed to the blade holder so that 15

it engages a feature, such as an end or a recess, on scraperblade 120.

An entire "family" of snap-engageable blades of differentlengths transverse to belt 12 to accommodate different widthbelts 12 and of different heights between skirts or legs 130and blade edge 122 is obtainable by simply modifying thegeometry, scale, and materials of blade 120 and/or blade

holder 110. For example, key-bar 114 could be incorporatedinto the geometry of scraper blade 120 and a mating femalegeometry such as a slot (instead of male) could be located on 25

blade holder 110. For brevity, this inherent capabili ty is onlynoted and is not described further herein.

An optional element of the invention is the inclusion ofthree optional bushings, best illustrated, for example, in FIG.3, as spring bushing 216 and rod bushings 30A, 30B. Springbushing 216 is located between blade holder rod 112 andtorsion spring 210 and extends through hole 234 in outercollar 230 and provides a smooth bearing surface for outercollar 230 and spring 210 to rotate upon. Bushing 216 alsohelps to keep material, e.g., food, contaminants and otherforeign matter, away from the circumferential crevice vol-ume between outer collar 230 and blade holder rod 112 at

their interface at hole 234, and it prevents materials fromlodging between spring 210 and blade holder 110. Optionalcylindrical bushing 216 serves to maintain the relativeposition of torsion spring 210 with respect to blade holderrod 112 where blade holder 110 passes through the centralopening of spring 210. Bushing 216 has an outer diameterthat permits it to be inserted within spring 210 and has aninner diameter that provides clearance for blade holder rod 45

112 to pass therethrough. In addition, optional bushing 216may include an extension of lesser outer diameter thatextends through clearance hole 234 in outer collar 230 forlimiting the relative displacement of the central axis of collar230 with respect to that of blade holder rod 112. Cylindricalbushing 216 may include only the portion within torsionspring 210, only the portion within clearance hole 234, orboth, and may be fabricated as one piece or in several pieces.

Rod bushing 30A is located on the tensioner 200 side ofconveyor 10 between inner collar 220 and mounting plate 50and preferably is a shouldered bushing that extends into thebearing surface region between mounting plate 20 and bladeholder rod 112. Bushing 30A provides a smooth bearingsurface for both the blade holder 110 to mounting plate 20interface and for the inner collar 220 to mounting plate 20face surfaces. Bushing 30A also prevents material fromentering tensioner 200 from through hole 28 in mountingplate 20, and it prevents material from lodging betweeninner colla r 220 and mounting plate 20. Rod bushing 30B islocated on mounting plate 20 on the side opposite tensioner200 and is of a unique, conical, one-t ime use, snap-in-placedesign. Bushing 30B provides a smooth bearing surface for

the blade holder 110 to mounting plate 20 interface. Afeature of bushing 30B is a short funnel shaped appurte-nance feature 31 oriented with its opening facing toward thecenter of conveyor 12 and co-linear, i.e. co-axial, with bladeholder rod 112. This specialized funnel 31 aids in guiding theinstallation of blade holder rod 112 into mounting plate 20at installation or following a system leve l cleaning opera-tion. Note tha t none of these bushings 30A, 30B and 216 arerequired to achieve a fully functional system, and in facttheir removal is recommended for certain ultra-sanitaryinstallations.

Tensioning arrangement 200 for scraper blade 120 isdescribed in relation to FIGS. 4 through 7 in which FIG. 4is a cross-section schematic diagram, FIG. 5 is a top-viewschematic diagram (with the locking handle 260 removedfor clarity), and FIG. 6 is an end-view schematic diagramshowing tensioning arrangement 200 of belt cleaning system10 of FIG. 1, and FIG. 7 is an end-view schematic diagramillustrating the tensioning adjustment arrangement of system

20 10 of FIG. 1. In this arrangement, optional bushings 30, 216are omitted.

The torsion spring 210 component of tensioning system

200 is located about the end of rod 112 of blade holder 110.Typically, spring 210 is rigidly affixed by welding 213, 215,or other means, to one or both of the collars 220 and 230,however, ends 212,214 of torsion spring 210 need not be soattached, but may be unsecuredly disposed in one of throughholes 236. While only one hole 236 is necessary to receivethe end 214 of torsion spring 210, a plurality of through

30 holes 236 is typically provided disposed in a circulararrangement of convenient diameter concentric with hole234. Where an adjustment tool is to be uti lized, as describedbelow, holes 236 are preferably in pairs disposed 180 0 apartaround the circle for receiving pins of the adjustment tool.

35 Outer collar 230 is provided with a centrally located clear-ance hole 234 which permits rotation of outer collar 230about the central axis CL of blade holder rod 112. Inner

collar 220 is, for example, a split-collar which provides aclamping action of collar 220 to rod 112, which passes40 through hole 224A to engage threads in hole 224B, when a

fastener 226, such as a socket-head cap screw, is advancedby turning to close radial slot 222. This clamping action issufficient to affix both the rotational and longitudinal posi-tion of inner collar 220 along blade holder rod 112.

The rotational and longitudinal position of the inner collar220 on rod 112 of blade holder 110 necessarily varies foreach installation depending upon the desired rotation andlongitudinal position of scraper blade 120, manufacturingvariances and tolerances in spring 210, and upon whether a

50 spring 210 with a left-handed or right-handed twist is used.Typically, during initial installation of cleaner system 10,inner collar 220 is "permanently" clamped to rod 112 ofblade holder 110 in a determined location, seldom, if ever,requiring adjustment or re -positioning thereafter. When

55 inner collar 220 is properly located, threaded radial hole 232in outer collar 230 will be accessible and centered on thecircumferential slot 270 located near distal end 252 ofhalf-can housing 250.

Half-can housing 250 is rigidly affixed, e.g., by welding60 254 to mounting plate 20 which is rigidly affixed to the

conveyor system 10 frame 16 or to another support orstructure, for example, either by welding or by utilizingfasteners through the provided thru-holes 24 and thru-slots22. Tension-locking handle 260 has a threaded stud 262

65 protruding from shouldered shank 266, which threaded stud262 engages into threaded hole 232 of outer colla r 230 afterpassing through slot 270 in half can housing 250. The end of



9US 7,083,040 B2

10threaded stud 262 proximate shank 266 is preferably notthreaded so as to provide a smooth bearing surface at theinterface between half can housing 250 and stud 262 atcircumferential slot 270. Handle portion 268 of tensionlocking handle 260 extends radially or at an angle withrespect to shank 266 and stud 262, and may also have a gripsuch as ball knob 269 of spherical or other shape, forconvenient gripping. Handle 260 may be of unitary con-struction or may be fabricated in two or more pieces andfastened together, e.g., by a screw or bolt 267.

By rotating tension-locking handle 260 (i.e. tightened, asshown by arrow 7B in FIG. 7), a clamping action occursbetween outer collar or flange 230 and the inner surface ofhalf-can housing 250. When tension-locking handle 260 hasbeen sufficiently loosened, thereby relieving the clampingaction between outer collar 230 and half-can housing 250,the outer collar 230 is released to be able to rotate about thecentral axis CL of blade holder rod 112 over a tensionadjustment range (as illustrated by arrow 7A of FIG. 7).Locking handle 260 is movable to and is lockable at anyangular position between positions A and B at the oppositeends of slot 270, thus inducing a torsional force on the spring

210. When properly applied, this torsional force is trans-ferred from spring 210 through inner collar 220, bladeholder rod 112, and key-bar 114 to scraper blade 120 whichis positioned against the conveyor belt 12 or similar surface.Locking handle 260 is positioned and secured in the posit ionwithin the tension adjustment range (illustrated by arrow7A) that provides the desired force urging blade edge 122 ofblade 120 against conveyor 12. The tension of spring 210 is 30

secured by rotating (arrow 7B) tension-locking handle 260until a sufficient clamping force is achieved to preventfurther rotation between outer collar 230 and half-can hous-ing 250. Tensioning is essentially infinitely selectable overthe range illustrated by arrow 7A, i.e. is continuouslyadjustable in that there are no fixed adjustment incrementsand handle 260 may be secured at any desired angular

rotation. In one typical embodiment, slot 270 has a lengththat provides about 120° total adjustment range, however,about 60° adjustment is typically provided in each directionaway from center position, which is where an axia l slot 272(shown in phantom) is preferably located, as more particu-larly shown and described in relation to FIG. 14 below. Thedirection (i.e. clockwise or counter-clockwise) in whichhandle 260 is moved with respect to slot 270 for adjustmentin any particular application of tensioning system 200 typi-cally depends upon which side of conveyor 12 that tensioner200 is mounted. These features are particularly desirable asapplied to light duty belts. Typical applications and tensionerparameters, such as tensioner spring rates, are set forth in theTable below:

Preferably, the outer diameter of collar 230 is preferablyabout the same as the inner diameter of the cylinder defininghalf-can housing 250, and inner collar 220 is preferably oflesser diameter. Thus, when locking handle 260 is tightened,outer collar 230 is held snug against the inner surface ofhalf-can housing 250 and is accurately positioned withrespect thereto, thereby also fixing the re lative positions ofblade holder rod 112 and end 214 of torsion spring 210.Because half-can housing 250 is likewise accurately posi-

10 tioned and attached to mounting plate 20, it is accuratelypositioned with respect to hole 28 in mounting plate 20, andbushing 30 therein, if utilized. As a result, all of torsionspring 210, inner collar 220, outer collar, half-can 250 andmounting plate 20, and the respective holes therein, are fixed

15 in predetermined relative posit ions that properly align withblade holder rod 112 to within desired tolerances.

Arcuate half-can housing 250 is affixed to and extendsfrom mounting plate 20 and is arcuate about an axis inter-secting mounting plate 20 proximate hole 28 therein, and is

20 preferably a cylinder whose central axis intersects hole 28.Outer collar 230 is spaced away from mounting plate 20 andhas an arcuate edge complementary to arcua te housing 250

and is rotatable with respec t to arcuate housing 250 about anaxis substantially intersecting hole 28, but which may be

25 misaligned therefrom. Inner collar 220 is rotatably disposedbetween outer collar 230 and mounting plate 20 and has athrough hole 224 adapted for receiving a member such asblade holder rod 112 and is rota table about an axis substan-tially intersecting hole 28, but which may be misalignedtherefrom.

Disassembly of blade assembly 100 including bladeholder 110, blade 120 and tensioner 200 is easily accom-plished by loosening and removing locking handle 260,removing blade 120, and then extracting blade holder 110,

35 spring 210 and collars 220, 230 from mounting plates 20 bymoving them away from conveyor 12. This easy and con-venient disassembly obtains whether ends 212, 214 of spring

210 are affixed to collars 220, 230 or are removably disposedtherein. Removal of bushing 30B provides sufficient clear-40 ance for key-bar 114 to pass through hole 28 of mounting

plate 20, but if such bushing is not utilized, then a radial slotin hole 28 is provided to allow release of rod 112 withkey-bar 114 therein. Alternatively, bushing 30B may besuffic iently large to pass blade holder 110 therethrough or

45 may be easily removable along with blade holder 110.Installation/assembly of blade appara tus 100 follows thereverse of the foregoing.

Vibration in belt cleaner 100 may cause tension-lockinghandle 260 to loosen and release during operation, thereby

50 causing an undesired change, i.e. reduction, in the pressureof scraper blade 120 against belt 12. To prevent this from

Tension Spring Torque Range AngularApplication Blade Width Rate (Desigu) Adjustment

Light Duty <44 inches 0.96 in-Ib/deg. 0-60 in-Ib ±60° ~ 120 0

(<112 em) (1.11 kg-em/deg.) (0-69.2 kg-em)Heavy Duty 44-96 inches 3.0 in-Ib/ deg. 0-180 in-Ib ±60° ~ 120 0

(112-244 em) (3.46 kg-em/deg.) (0-207 kg-em)Extra- 96-120 inches 6.0 in-Ib/deg. 0-360 in-Ib ±60° ~ 120 0

Heavy Duty (244-305 em) (6.92 kg-em/deg.) (0-415 kg-em)

Typically, scrapers of greater than about 79 inch width 65

(about 200 ern) utilize two tensioners 200, one at each endof blade holder rod 112.

occurring, an optional anti-vibration or locking device, suchas Belleville washer 264 or other locking-type washer ordevice, is used on tension-locking handle 260 between the



11US 7,083,040 B2

12shoulder of shouldered shank 266 and the outer surface ofhalf-can housing 250. Additionally, tension-locking handle260 has a position adjustable feature that allows the rota-tional posit ion of handle 260 to be adjusted, i.e. rotationallywith respect to shank 266 and threaded stud 262, withoutaffecting the already applied clamping force. This feature isimportant for safety purposes (i .e . handle 260 won't "stick-out" from the side of the conveyor 10 in a direction awayfrom mounting plate 20) and where a limited clearanceexists which prevents full 360 0 rotation of handle 260 whenit is being tightened or loosened. Tension locking handle 260also has a ball knob 269 to improve hand grip and preventhand-slipping, a common problem in the food industrywhere workers often have wet and slippery hands.

The present invention includes improvements to theASGCO RotoTwist™ torsion spring tensioning systemdescribed in U.S. Pat. Nos. 5,201,402 and 5,992,614 andvarious embodiments may provide one or more of thefollowing features and/or advantages:

(1) infinite set-abili ty of the spring tension (non-discreetcontinuous adjustment of tension rather that only dis-creet set points) over the entire operating range,

(2) single-handed setting (by one person) of the springand blade tension without requiring the use of handtools or a second person,

(3) direct and simultaneous tensioning of the tensionspring and blade,

(4) a torque-limiting device that prevents the under-t ightening or over-tightening of the tension-lockingclamp handle,

(5) precise and repeatable tensioning of the tension springand blade using a torque wrench, with and without aspecialized tool,

(6) design and configuration to meet the most stringentsanitary design and cleanability requirements (espe-cially through the use of an open external springtensioning device which is accessible and easily sani-

tized),(7) a "half-can" protective housing that greatly reduces orprevents the deposit and/or accumulation of staticmaterials upon the tensioning unit while simulta-neously providing a means for rigidly fixing the outerportion of the spring tensioner to the conveyor frame,and

(8) a unitary tensioner (tension spring and inner and outercollars) and blade holder that is quickly and easilyremovable as a unit from the mounting plates andhalf-can housing, such as for cleaning; and

(9) a graduated scale on the half-can housing associatedwith an index feature on the outer collar that indicates 50

the relative rotation of the tensioning unit, from whichthe applied pressure of the scraper blade against theconveyor belt can be inferred or estimated.

In addition, the invention facilitates an IPC cleaningoperation. Many conveyance systems and related equipmentused, for example, in the food industry are cleaned on aregular (e.g., daily) basis utilizing IPC techniques. IPCcleaning often involves the use of high pressure spraywashers, various hand brushes, and ideally involves a mini-mized amount of in-place disassembly. The unique "open- 60

architecture" (accessibility) of the system according to theinvention makes it particularly amenable to effective andconvenient IPC type c leaning. Four elements contribute toand/or cooperate to provide this feature, First, the snap-onblade is easily removed, cleaned, and re insta lled. Second,the half-can housing and open-helix torsion spring allow thetensioning system to be effectively flushed by the pres sur-

ized spray. Third, the elimination of set-screws, blind holes,unsealed crevices and other material entrapment volumes,which are commonly found on other commercially availableconveyors, enables IPC to be recommended. Finally, there-tensioning of the system is easily and rapidly accom-plished without requiring hand-tools. For a belt scraping/cleaning system contemplated for use in this manner withIPC cleaning, removal of the spring and blade holder rodbushings is preferred (this is permissible and does not

10 adversely affect functionality, particularly where the springis welded to the inner and outer collars and/or where theholes in the mounting plates for the blade holder rod aresized for use without bushings.

For certain, albeit rare, applications in which the most15 severe cleaning and/or sanitation requirements are imposed,

i.e COP cleaning at frequent intervals, the inventive beltcleaner system is rapidly extracted from its mounting sup-ports without requiring the use of hand tools. This facilitates,for example, submersive COP cleaning in an ultrasonic bath.

20 Operationally, the disassembly is accomplished by firstremoving the snap-on cleaner blade. The tension-lockinghandle is then removed from the outer collar and half can

housing. The blade holder and tensioning system assemblyis then longitudinally removed from the half can housing.

25 Sufficient clearance is provided in the centrally located holein the mounting plate to which the half can housing isattached to permit passage of the blade holder rod withkey-bar, and if a bushing is employed, such clearance isprovided in the bushing or by its removal.

In the case where the tension spring is not fastened toeither the inner or outer collar, but has ends that reside inholes therein (which is permissible), the tensioning system(including bushings, if used) slides off the end of the bladeholder. The inner collar remains on the blade holder, and

35 usually wouldn't require removal therefrom for sufficientcleaning. A further improvement upon this arrangement is tohave an additional axial slot 272 in the half can housing

(described below) that is transverse (i.e. at an angle) withrespect to the existing circumferential or arcuate slot and of40 about the same width, and extending axially from the

existing slot to the distal end of the half can housing. Thisaxial slot 272 "opens up" one side of the existing tensionadjustment slot so as to eliminate the need for removal of thetension-locking handle from the outer collar for disassem-

45 bly.In the case where the tension spring is fastened to either

the inner or outer collar (which is permissible), the tension-ing system (including bushings, ifused) slides off the end ofthe blade holder. The inner collar remains on the bladeholder, and usually wouldn't require removal therefrom forsufficient cleaning. Alternatively, in the case where thetension spring is fastened to both the inner collar and theouter collar (which is preferable), the tensioning system andblade holder (including bushings, if used) slides out of the

55 mounting plates as a unitary member or assembly. Theadditional axial slot 272 in the half can housing is advan-tageous in this arrangement to facilitate quick and easyremoval of the tensioner/blade holder as an assembly with-out removal of the clamp handle.

FIGS. SA, SB and SC are side-view, end-view and cross-section view schematic diagrams, respectively, of an exem-plary tension adjustment tool 1230 suitable for use with thetensioning system 200 of FIGS. 4-7. Outer collar 230 isequipped with a number of equally spaced and sized through

65 holes 236 that allow for the engagement of a tensionadjustment tool 1230. Exemplary tool 1230 has two pins1236 extending parallel from tool body 1232 and designed

30



US 7,083,040 B213 14

FIG. 9 is a cross-section schematic diagram showing analtemative embodiment of a portion of the tensioningarrangement 200 of FIG. 4. Among the problems anticipatedis the case where a very strong worker applies excessivetightening force to tension-locking handle 260 or the oppo-site case where too little tightening force is applied toprovide adequate clamping force to secure locking handle260 and outer collar 230 in position relative to half-canhousing 250. To prevent this from occurring a uniquelyapplied torque limiting knob 260' replaces tension-lockinghandle 260. Knob 260' includes a built-in clutch-like mecha-nism 261 at the interface between threaded stud 262' andhandle 263 which operates to slip at a predetermined torque,i.e. in a manner similar to most modem motor vehicle gascaps. When the proper tightening force is applied, internal

s ized to receive the end of blade holder rod 112 that extends clutch 261 ofknob 260' sl ips and prevents further t ightening,through clearance hole 234 in outer collar 230. prevents over tightening. When knob 260' is under tight-

Tool 1230 provides a feature that can be important in ened, clutch 261 thereof does not slip, thereby indicating toapplicat ions where precise tensioning is required to ensure the operator that it is not sufficiently tightened. Sui tableproper performance of the cleaning system or when over- 20 adjustable-torque clamping knobs are readily available, suchtensioning could harm the conveyor belt , as in the case, for as from McMaster-Carr company and others.example, where the belt has a thin polyolefin top-cover and FIGS. lOA, lOB and 10C are a side-view schematic

is susceptible to excessive wear or damage from an over- diagram showing an exemplary blade holder 110, and endtensioned bel t cleaner. Tool 1230 can be removed from outer view schematic diagram showing an exemplary scrapercollar 230 following each use, or may be left in place 25 blade 120 and an end view schematic diagram showingbetween uses. Alternative embodiments of a tool of this sort engagement of scraper blade 120 with blade holder 110, ininclude: an extended torque arm, a palm-shaped end-knob, accordance with the invent ion. Blade holder 110 comprisesand a built in torque indicator, for example. a solid metallic rod 112 that includes a longitudinally

One inherent and valuable built -in safety feature of the aligned metall ic key-bar 114 that is co-located in proximitysystem 100 of the invention is the ability to limit the 30 to snap-onlsnap-off scraper blade 110. Key-bar 114 pro-maximum tension applied to tension spring 210. In certain trudes beyond the circumference of blade holder rod 112 toapplicat ions, for example, conveyor belt 12 is of relatively engage into a mating socket or longi tudinal s lot 134 locatedlight material and somay be easi ly damaged if scraper blade in longitudinal cyl indrical cavity 132 of snap-on scraper120 is over tensioned, thereby producing a loss of produc- blade 110. Key-bar 114 fixes the rotational posi tion of bladetion and the expense of bel t replacement . Optional ly, the 35 120 with respect to blade holder 110 and transmits thetension applied to blade 120 may be l imited by accurately tors ional force applied bytors ion spring 210 to scraper bladeadjusting the rotational positioning of inner collar 220 on 120, thereby causing scraper blade 120 to impart a force to

blade holder rod 112 such that the rotation of spring 210 by belt 12 across the blade/belt interface. Key-bar 114 alsoouter col lar 230 is restricted to a predetermined and/or safe reacts against forces externally appl ied to scraper blade 120value by locking handle 260 reaching the end of its possible 40 (which may include forces that are potentially damaging tophysical travel in slot 270 of half-can housing 250. blade 120 and/or blade support 110) and transmits such

To this end, the angular position at which half-can hous- forces back to torsion spring 210 via blade holder rod 112ing 250 is fixedly mounted, such as by welding, to mounting and inner collar 220.plate 20 is carefully controlled as is the angular position of The "cylindrical" geometry of blade holder rod 112 isinner collar 220 with respect to blade 120 on blade holder 45 chosen to facilitate the shedding of and to prevent the110 (i.e. with respect to blade tip 122). Actually, the relative undesired build-up of material on the blade holder 110angular position of collar 220 may be controlled with respect surface. The length L of key-bar 114 is preferably aboutto key-bar 114ofblade holder rod 112, thereby placing blade equal to the length of blade 120, however, key-bar 114 doestip 122 in a known position because the size and shape of not necessarily need to be continuous over the entire lengthblade 120 is known. This controls the angular rotational 50 L of blade 120 and could be installed as adjacent or asangle of tension spring 210 assembly 210, 220, 230 relative discont inuous sections over the blade 120 length. Key-barto the blade 120 and the position of locking handle 260. 114 is permanently affixed into a precision machined lon-Thus, the range ofpossible movement of locking handle 260 gitudinal slot 115 located inblade holder rod 112 and affixedin angular slot 270 is controlled and limited such that the by any of several means, including welding, mechanicalmaximum desired level of spring tension (blade 120 pres- 55 staking, shrink-fitting, or with application of adhesive, suchsure) is reached when locking handle 260 reaches the as food-grade adhesive. The overall length of blade holdermechanical limit of its rotational travel (i.e. the end of slot rod 112 is determined by the length L of blade 120 plus270). additional length on each end to extend blade holder 110

Alternatively, a position adjustable device may be pro- beyond each of mounting plates 20 and the tensioning unitvided on half-can housing 250 for restrict ing the travel of 60 200 outer collar 230 on the side with tensioning system 200.locking handle 260 along slot 270. Alternat ively or addi- For certain (typical ly very wide belt -width) applications, i ttionally, graduated scale 280 (e.g., FIG. 6) may be inscribed might be desirable to have two tensioning units, one on eachor otherwise placed on the rim or end 252 of half can side of conveyor belt 12, i.e. one at each end of blade holderhousing 250 to be used with index feature 282 on outer rod 112. In these cases the length of blade holder 110 iscollar 230 to indicate the rotation of collar 230 with respect 65 extended to accommodate each of the two tensioners 200.to half-can housing 250, thereby facilitating setting and/or Typically, key-bar 114 and rod 112 are fabricated fromresetting the tension when required. stainless steel, however, other materials of construction can

to slideably engage into a pair, i.e. two, of through holes 236in outer collar 230 and to be held in place therein by detentpins or ball detents 1237, although a greater number of pins1236 could be provided. Pins 1236 are spaced apart the samedistance as the diameter of the circle on which opposing 5

ones of holes 236 are disposed on outer collar 230. Non-circular hole 1238 in tool body 1232 provides a means forattaching a torque measuring device, such as a torquewrench or other torque-measuring device, for allowing pre-cise and repeatable adjustment of the spring tension. Hole 10

1238 is typically square or hexagonal so as to be compatiblewith conventional socket wrenches and socket wrenchdrives, but may be triangular, octagonal or any other shapethat can non-rotatably engage a torque wrench or otherinstrument or tool. Tool 1230 also has a clearance hole 1234 15



15US 7,083,040 B2

be used including: steel, surface-treated steel, aluminum,and plastics (e.g., nylon). Stainless steel is often mostdesired for food manufacturing applications for the obviousreasons of cleanability, corrosion-resistance, and aesthetics.As recommended by the Baking Industry Sanitation Stan- 5

dards Committee (BISSC), the surface finish on these parts,as well as the elements of tensioner 200, will typically be<70 micro inches (average) for food-grade applications.

Additionally, blade holder 110 includes at least oneengaging feature 116, such as fixed metallic pin 116, which 10

extends radially from rod 112 in substantially the samedirection as does key-bar 114. When engaged into a matingsocket or recess (not visible) on snap-on scraper blade 120,pin 116 provides an engaging feature 116, i.e. a means, forfixing the longitudinal position of blade 120 along blade 15

holder 110 to prevent lateral or sidewards movement ofblade 120 with respect to blade holder 110. Fixed pin 116 ispermanently attached to blade holder rod 112 by press- fittinginto a mating blind hole 117 and is typically of like material.To further ensure the permanent fixing of pin 116 in rod 112, 20

it is welded, adhered, or staked in place, in l ike manner tokey-bar 114. Fixed pin 116 may be located at any suitable

location along the length of blade holder rod 112.Instead of a pin 116, engaging feature 116 could also be

another suitable shape, for example, a smooth-surfaced 25

hemisphere or semi-sphere (a portion of a hemisphere) orother shape that is acceptably designed to engage a corre-sponding recess in blade 120 to restrain the lateral freedomof movement of blade 120. The hemisphere or semi-spheredesign is desirable since the mating socket on snap-on 30

scraper blade 120 is easily cleaned. Alternatively, the pro-truding engaging feature can be on blade 120 and thecorresponding recess on blade holder 110.

As previously described, scraper blade 120 is preferablyfabricated from elastomeric/plastic materials and is uniquely 35

designed to permit legs 130 to snap-engage onto and tosnap-release from rod 112 of blade holder 110. The main

function ofblade 120 is to dislodge material being carried byconveyor belt 12 to be dislodged therefrom by scrapingaction. Blade-tip 122 is the location where blade 120 makes 40

contact with conveyor belt 12. The shape of blade-tip 122 isconfigured to facilitate an effective scraping action whenheld against the conveyor belt 12 at an appropriate angle andapplied pressure. Blade-tip 122 continuously wears through-out its service life, thus causing the effective radial length of 45

blade 120 (i.e. the distance between centerline CL of rod 112and tip 122) to decrease over time. Torsion spring 210accommodates this wear and acts to maintain a near constantforce at blade-tip 122. As blade 120 wears, the decrease inspring force that would result tends to be somewhat com- 50

pensated by the shorter radial length between blade holderrod 112 and tip 122 of blade 120, because the force (F r) attip 122 equals the spring 210 torque (T) divided by the radialdistance (Rr) of tip 122 from rod 112, i.e. Fr=T/R r

Blade 120 is deliberately shaped so as to provide an 55

efficient scraping action with minimal residual material,which shape can generally be appreciated from FIGS. 1 and2, and from FIGS. lOB and 10C. Contoured-side 126 ofscraper blade 120 is deliberately shaped to efficientlyenhance shedding and expulsion of material from tip 122 60

and side 126 ofblade 120. The flat-side 124 of scraper blade120 has a shape that facilitates the shedding of material thatundesirably passes blade-tip 122 and adheres to what is theback-side of blade 120 (at least when used in a primaryscraper configuration bearing against the belt 12 as it passes 65

over head pulley 14). Flat surface 124 ensures the continuedexistence of an effective scraping angle (i.e. an acute angle)

16between blade-tip 122 and conveyor 12 throughout theservice life of blade 120. The surface finish, of both thecontoured and flat sides of the blade, is normally <70 microinches (average), as is desirable to minimize adhesion offoreign matter and improve cleanability in food-grade appli-cations.

One unique feature of scraper blade 120 is the dualfunction performed by the pair of opposed legs 130. Legs130 are designed to perform as "skirts" while simulta-neously providing the snap-on functionality. Legs 130,which are slick (low coefficient of friction) smooth con-toured surfaces similar to the rest of blade 120, prevent thebuild-up of material on the blade holder 110 by extendingthe sides, i.e. the flat surface 124 and the contoured surface126, of blade 120 and minimizing exposure of the surfacesof blade holder 110. The novel snap-engagement function,i.e. snap on installation and snap off disassembly, is accom-plished by allowing legs 130, which define a longitudinalcylindrical cavi ty 132 in blade 120, to semi-elasticallydeform by extending outward (arrows 131 in FIG. 10C) assnap-on blade 120 is pressed (arrow 133) over blade holderrod 112 and key-bar 114. As rod 112 reaches full engage-

ment, legs 130 nearly encircle rod 112 which is thendisposed in cylindrical cavity 132. If properly designed, e.g.,with the diameter of cylindrical cavity 132 when emptybeing slightly less than the diameter of rod 112, legs 130 donot return to their rest position, but remain partially spreadthereby applying a slight clamping force against bladeholder rod 112. This provides a desirable and unique featurethat enables a passive sealing action between the interiorcavity 132 portion of snap-on-blade 120 and blade holder110.

Longi tudinal key-bar mating slot 134 is located withincavity 132 and dimensioned to engageably accept the key-bar 114 during installation of snap-on-blade 120 onto bladeholder rod 112. A chamfer or fillet 136 is provided at theinsertion edge of longitudinal slot 134 to aid in guiding

key-bar 114 into slot 134. Another fillet is located at the baseof key-bar mating slot 136 so as to provide a smoothtransition between the bottom surface and the side surfacesthereof, thereby to facilitate cleaning and to prevent theaccumulation of material along the interior comers of slot134.

Another unique feature of the inventive system is themauner in which snap-on scraper blade 120 can be removedfrom blade holder 110 to facilitate regular cleaning and/orperiodic blade replacement. This removal operation is per-formed after relieving the tension of blade 120 againstconveyor belt 12, which is accomplished by looseningtension-locking handle 260 and rotating handle 260 alongthe length of slot 270 of half can housing 250. There areseveral methods that can be employed to remove the blade.The simplest method is to apply sufficient force, using one'sfingers, to legs 130 parallel to key-bar 114near either end ofblade 120, causing blade 120 to "un-snap" from blade holderrod 112. This method is viable whenever the surface of blade120 is not too slippery or adhered material is not hamperingits removal from holder 110. The design of blade-holdinglegs 130 takes into account the force required for fingerremoval of blade 120, and this method is designed to workfor many applications and blade materials.

FIG. 11 is a schematic diagram illustrating removal of asnap-on blade 120 using an exemplary L-shaped tool 1140,in accordance with the invention. "L" -shaped hand tool 1140engages key-bar slot 134 at the end of blade 120 and thenlever handle end 1118 of tool 1140 is moved to apply apulling force to separate and disengage blade 120 from



17US 7,083,040 B2

holder rod 112, either directly or by lever ac tion. When thismethod is used, the length of key-bar 114 is intentionallymade shorter than the length of blade 120 to provide anengagement volume at an end thereof sufficient to receivelever tool end 1114 of "L"-shaped hand tool 1140. Another 5

method of blade removal involves sliding blade 120 off theend of blade holder rod 112 on the side opposite tensioningsystem 200. This approach is useful whenever system-levelextraction is performed, (i.e., "tensioner" 200 and bladeholder 110 are also being removed). Another method using 10

an "L" -shaped tool is described below.FIGS. 12A and 12B are side-view and top-view schematic

diagrams, partially in cross-section, of an alternative exem-plary blade-removal lever mechanism 1140', FIG. 12C is aside-view schematic diagram of the lever 1114'-1116thereof, FIG. 12D is a cross-section view schematic diagramthereof, and FIGS. 13A and 13B are side-view and end-viewcross-section schematic diagrams of the blade-removal levermechanism 1140' of FIGS. 12A-12D when fully actua ted,all in accordance with the invention. In certain applications, 20

there is a need for a built-in mechanical device capable ofimparting a significant force to urge blade 120 off of blade

holder 110, such as in those cases where significant adhesionexists between blade 120 and blade holder 110. A novelbuilt-in lever-type mechanism 1140' that allows for theforceful extraction of snap-on blade 120 is located inside acavity 113' of blade holder 110 at any desired location alongthe blade length. Typically, a channel-slot 1113' is machinedinto blade holder rod 112' to a llow lever mechanism 1140' tobe inserted into blade holder 110 and a through hole 1115made in rod 112' transverse to the machined slot. A portionof key-bar 114 is eliminated or removed from the region oflever mechanism 1140' leaving key-bar 114'.

"L"-shaped lever 1114'-1116 comprises an extended armor lever tool section 1114' of similar cross-sectional size andshape to key-bar 114' that when not actuated resides a longthe region that would be occupied by key-bar 114' but for it

being removed to provide for lever mechanism 1140' . Lever1114'-1116 also comprises a handle section 1116 that isdisposed in cavity 1113' of rod 112' and that includes athreaded hole 1115 which accepts a pair of socket-head capscrews 1118' inserted from both sides of rod 112' formounting and actuation. The shank of each socket head capscrew 1118' passes through opposing clearance holes 1115that are provided in blade holder rod 112' and are transverseto the centerline thereof. Socket head cap screws 1118'provide support and locate lever mechanism 1114'-11116 bycentering their shoulders inside clearance holes 1115 inblade holder rod 112. Socket head cap screws 1118' aresufficiently tightened against each other to lock up and 50

permanently fix their rotation with respect to lever1114'-1116 inside lever-mechanism 1140'. Additional meansof fixing cap screws 1118' with respect to lever 1114'-1116may be provided by welding or staking to prevent futurerotation with-in the body oflever mechanism 1140' . Becauseextended arm 1114' of lever mechanism 1140' has a cross-sec tion nearly identical to blade holder key-bar 114', whenblade 120 is attached to blade holder 110, extended arm1114' is engaged into key-bar mating slot 134 of blade 120.

Blade removal is accomplished by first engaging a hexkey tool (not shown) such as a conventional Allen wrench,into the socket head of either or both of cap screws 1118'.Turning the hex key tool in the appropriate direction (i .e. forrotation of cap screw 1118') causes lever tool portion 1114'of lever-mechanism 1140' to swing deeper into matingkey-bar slot 134 of blade 120. By causing the lever-mecha-nism 1140' to fully-actuate, blade 120 is sufficiently trans-

18lated radially away from rod 112' to locally free it from bladeholder 110. By simple hand-action blade 120 is thenremoved the rest of the way. Lever mechanism 1140' alsoprovides longitudinal restraint of blade 120 against move-ment along blade holder 110 using the socket head of one orboth of cap screws 1118'. To accommodate the sockethead(s) of cap screws 1118', small open-ended slots ornotches 121 are provided in legs 130 of snap-on blade 120.Engagement of notches 121 of legs 130 about the heads ofcap screws 1118' causes blade 120 to be laterally restrainedalong blade holder 110, thereby eliminating the need forearlie r described fixed pin 116 on key-bar 114 and a corre-sponding mating socket on blade 120.

Alternative embodiments and variations to embodiments15 of belt scraping system 10, including blade tensioner 200,

scraping blade 120, and blade holder 110, described abovein relation to FIGS. 1-13 are described in relation to FIGS.14-20 following. Certain of these alternatives and variationsfacilitate assembly and disassembly of scraping system 10and/or scraper blade 120, while others are directed tofacili tating the setting and/or adjustment of blade tension.

FIG. 14 is an isometric view schematic diagram of an end

of tensioning arrangement 200 of system 10 of FIGS. 1through 7 including an additional axial slot 272 in half-can

25 housing 250 thereof for facilitating assembly and disassem-bly of scraping system 10. Half-can housing 250 is asdescribed above except that axial slot 272 of similar widthto circumferential slot 270 is added. Axial slot 272 allowsfor passage of stud 262 of locking handle 260 from slot 270

30 without its removal from outer collar 230. Thus, lockinghandle 260 is rotated (loosened) to release the pressurefixing outer collar 230 in relation to half-can housing 250and locking handle 260 is moved along slot 270 and throughslot 272 so as to be released and free from half-can housing

35 250. Because handle 260 is threaded into outer collar 230,outer collar 230 is likewise released and free from half-canhousing 250. Further, torsion spring 210, blade holder 110

and inner collar 220 are likewise free to be removed (withthe release of collar 230), all without disturbing monnting40 plates 20 and half-can housing 250 from their fixed posit ions

in the desired alignment with respect to conveyor 12. If ends212, 214 are fixed, e.g., welded or adhered, to inner collar220 and outer collar 230, as they may be, then the entireassembly of blade holder 110, spring 210, collars 220, 230

45 and handle 260 are removed as a unit from the mountingarrangement 20,250. Even if ends 212, 214 of spring 210 arenot fixed to collars 220, 230, the parts 110, 210, 220, 230,260 may be grasped and removed together as if they were aunit. It is noted that blade 120 is removed from blade holder110 prior to removal of blade holder 110 from monntingplates 20.

As a result, blade assembly 100 may easily, quickly andconveniently be removed either as pieces 230/260, 220, 210,110, or as a unit (blade 120 having been removed), thereby

55 to facili tate cleaning, whether at the location of conveyer 12as by IPC or remotely therefrom as by COP. Further, theremaining monnting plates 20 and half-can housing 250 arevery open and so may be easily cleaned and sanitized inplace. In addit ion, threaded through hole 232 in outer collar

60 230 also allows an additional handle such as a cylindrical ora ba ll-knob handle 260F to be threaded therein in a position180 0 opposed to locking handle 260, which can aid anopera tor in adjusting the spring and scraper blade tension.Alternatively and/or additionally, optional graduated scale

65 280 on end 252 of half can housing 250 is used with indexfeature 282 on outer collar 230 for setting and/or resettingthe tension when required.



19US 7,083,040 B2

20FIG. 15 is an isometric view schematic diagram of an

alternative exemplary scraping system arrangement 100' inaccordance with the invention, and

FIGS. 16A and 16B are end-view and side-view cross-section schematic diagrams, respectively, of an alternative 5

embodiment of an outer collar 230 suitable for use in, forexample, the tensioning arrangement 200 of FIG. 4 or 15.

As above, scraping system 100' includes a snap-onscraper blade 120 mounted on a blade holder 110 rotatablysupported by mounting plates 20. Blade holder 110 and 10

scraper blade 120 are tensioned against a conveyor belt bytensioner 200 including torsional spring 210, inner collar220, outer collar 230 in coopera tion with half-can housing250, wherein the desired tension is maintained by clampingdown of tension-locking handle 260. Among the variations 15

are that monnting holes 24 in monnting plates 20 are"T"-shaped slots 22' rather than being elongated slots 22,thereby to facilitate the installation and proper positioning ofthe scraping system to conveyor belt 12 and its supportstructure 16, as well as the making of any adjustments as 20

may become necessary or desirable in operation.In system 100', outer collar 230' is solid and includes a

coaxial or concentric hexagonal head 238 extending there-from to which a conventional torque wrench may be appliedfor setting a desired scraper blade tension. Because hexago- 25

nal head 238 is centrally or concentrically located on outercollar 230' , its central axis is substantially co-l inear with theaxis of rotation of blade holder 110, so that the torqueapplied to hexagonal head 238 is directly related to thetorque applied to scraper blade 120 through blade holder 30

110, inner collar 220 and tension spring 210. As a result, thetension of spring 210 (and thus the pressure at blade 120)may be precisely and repeatably applied and set.

In addition, the need for a special tensioning tool (e.g.,tool 1230 of FIG. 8) and for extra holes 236 in outer collar 35

230 to receive the tool, are avoided. As a result, outer collar230' is simplified and, in particular, need have only two

through holes, i.e. one threaded hole 232 that receivesthreaded stud 262 of tension-locking handle 260 and onethrough hole 236 that receives end 214 of tension spring 210 40

which may rest therein or be welded or otherwise fastenedtherein.

Preferably, tension spring 210 is welded to inner and outercollars 1220, 230 so as to be a unitary member or assemblythat is easily removable as a unitary member by releasingclamp 260 and moving it through longitudinal slot 272.Because inner collar is fastened to blade holder 110, bladeholder 110 and such unitary assembly of spring 210 andcollars 220, 230 are easily removed together.

It is noted that collar 230' has fewer holes and openingsin which food or other debris can accumulate, therebyfacilitating cleaning and maintenance. Threaded throughhole 232 in outer collar 230' also allows an additional handlesuch as a cylindrical or a ball knob handle 260F to bethreaded therein 180 0 opposed to locking handle 260.

Outer collar 230' may have one or more additional holes236 if it is desired that one type of outer collar 230accommodate tension springs 210 of different strengths,such as a light-duty spring (smaller diameter helical ele-ment) and a heavy-duty spring (larger diameter helical 60

element), as shown in FIG. 16A. Spring 210 may be weldedinto hole 236 in outer collar 230' , thereby eliminating a holeor crevice in which debris can accumulate. It is noted thatblade holder 110 is adequately supported and rotatablymounted by inner collar 220 and holes 28 of mounting plates 65

20, and that tension spring 210 and outer collar 230, 230' a reboth adequately supported by inner collar 220 and tension-

locking handle 260, and so there is no need for a hole inouter collar 230, 230' to receive an end of blade holder rod112. The support of blade holder 110 at holes 28 of mountingplates 20 may employ a suitable bushing 30, such as abushing 30, 30A, 30B described above, which may be ofUHMW-PE, Delrin®, PTFE, nylon or other plastic.

FIGS. 17A and 17C are side-view schematic diagrams,respectively, of an exemplary alternative blade holder 110'and a complementary alternative scraper blade 120' therefor,and FIG. 17B is a cross-section schematic diagram of theblade holder 110' of FIG. 17A,

Blade holder 110' includes a key-bar 114' extending froma longitudinal slot 115' in blade holder rod 1112 to engagesnap-on scraper blade 120 installed thereon in a prede ter-mined angular (i.e. radial) position. Indexing feature 116'extends or protrudes from the flat outer surface of key-bar114' to provide a transverse position indexing feature. Forexample, a screw, rivet or pin having a hemispherical head(or other shaped head) may be driven into a hole in key-bar114'. Thus, scraper blade 120 and blade holder 110 aremaintained in a preferred relative transverse (i.e. axial)position by pin 116' projecting from key-bar 114' so thatblade 120' is in a desired transverse position with respect tothe width of conveyor belt 12. Correspondingly, one or moreindexing features 136 along key-bar mating slot 134 ofscraper blade 120' are provided to engage with indexingfeature 116' of key-bar 114' to position blade 120' at one ormore selected longitudinal positions with respect to bladeholder 110', thereby providing for transversely indexedposit ioning of scraper blade 120' with respect to the width ofconveyor belt 12. Scraper blade 120' is thus slideablyindexed along blade holder 110' to provide for simplified andexpedient adjustment of the lateral position of blade 120'along blade holder 110', i.e. relative to conveyor 12.

FIG. 18 is a schematic diagram of an alternative embodi-ment showing an exemplary scraper blade 120D formed oftwo different materials. Blade 120D has a blade tip portion123 that is formed of a soft plastic, such as a thermoplasticresin (TPR) to define a blade edge or tip 122 that is soft andcompliant, as is desirable for use with a belt having a softcover or as a "squeegee" with a wet belt. Blade 120D has abase portion 125 that is a resilient body formed of a resilient

45 plastic material, such as the materials described above inrelation to blade 120, that has sufficient strength and resil-iency so that resilient skirts 130 releasably grasp a bladeholder 110 as above within cavity 132 for installation andremoval in a snap-on-snap-off marmer. The materials of

50 resilient body 125 and soft tip portion 123 are selected ofcompatible materials that strongly bond to each other alongbond surface 127, and are preferably of food grade materialswhere intended for food processing usage. Soft tip portion123 preferably is of a Sanoprene thermoplastic e lastomer

55 material having a durometer of about 85 Shore A and bodyportion 125 is of PVC or polyurethane or similar food-gradematerial having a durometer that is substantially higher, e.g. ,100 Shore A or higher.

FIG. 19 is a schematic diagram of an alternative embodi-ment showing an exemplary tall scraper blade 120T forsnap-on installation on blade holder 110 and snap-offremoval therefrom. One feature of the invention provides aunique, easy-to-install and easy-to-remove, snap-onlsnap-off blade and corresponding blade holder suitable for a"family" of blades and blade holders adapted for part icularapplications. The blade's "legs" not only perform as skirts toshed scraped material and provide for the snap-onlsnap-off



2 1

US 7,083,040 B22 2

feature, but also provide, due to the legs' residual clamping-force action, a passive sealing of the blade against the bladeholder.

Tall scraper blade 120T is like blade 120 described aboveand is modified to have a greater dimension between bladetip 122 and skirts 120 and to have a shaped side surface 124'.Side surface 124' is shaped either by a number of adjacentflat segments 124a, 124b, and so forth, or by a continuousarcuate surface which mayor may not have a constant radiusof curvature. Longitudinal cavity 132 may be cylindrical or 10

may be of other shape, such as hexagonal cross-section asillustrated, so as to receive blade holder rods 112 that arecylindrical or of corresponding cross-section, such as hex-agonal. Tall blade 120T is adapted for application whereadditional blade "reach" is desired, as is often the case for 15

primary (head pulley 14) cleaners, particularly where thediameter of head pulley 14 is small, e.g., 1-6 inches (about2.5-15 em). This arrangement allows the blade holder 110centerline CL to be sufficiently removed from the pulley 14centerline to allow blade holder 110, mounting plates 20 and 20

tensioner 200 to clear the support structure of pulley 14,such as pillow blocks, bearing assemblies and head pulley

drive components.FIG. 20A through 20C are a side-view, end-view and

end-view cross-section schematic diagrams, respectively, 25

showing an alternative exemplary long-span blade holder110" and a snap-onlsnap-off scraper blade 120 therefor inaccordance with the invention. Long-span blade holder 110"is useful where it is desired to employ the invent ion with ablade holder 110 of great width, e.g., greater than about 30

50-60 inches (about 125-150 em), as may be necessarywhere either the conveyor 12 or the conveyor supports 16are widely spaced, or where it is desired to have the bladeedge 122 of blade 120 positioned at a greater radial distancefrom the axis of rotation CL of blade holder 110, or where 35

it is desired that the blade 120 is positioned at an angle withrespect to (rather than substantially perpendicular to) the

direction of travel of conveyor 12. Blade holder offset rod118 and blade holder central rod 112 (which is rotatableabout the axis ofrotation CL ofblade holder 11 0") are joined 40

and connected by blade holder web 119. The cross-section ofblade holder 110" is that of a dumb-bell or an I-beam whichprovides greater rigidity and resists twisting and/or bending.Web 119 also positions blade edge 122 further from axis ofrotation CL of blade holder 110". The assembly of rods 112 45

and 118 by web 119 and key-bar 114 may be held togetherby suitable adhesive or by welding, as is convenient. Rods112 and 118 are typically solid %-inch diameter stainlesssteel rods and web 116 is Ijs-inch-thick stainless steel. It isnoted that while the length of blade holder rod 112 may be 50

quite long, the length of offset rod 118 and of blade 120mounted thereon my be substantially shorter. Long-spanblade holder 110' can accommodate blades 120 of longlength, e.g., lengths of about 10--16feet (about 3-4 meters).

For food processing applications, metal parts, such as 55

blade holder 110, 110', 110", tension spring 210, inner andouter collars 220, 230, 230', half-can housing 250, mountingplates 20, handles 260, and the like are preferably stainlesssteel, and more preferably are corrosion-resistant, electro-polished 300-series stainless steel. Stainless steel and other 60

metal parts may be finished to a 70 fl-inch surface finish forsanitary as well as appearance reasons. For food processingapplications, scraper blade 120, 1120 and spring bushing216 and bushings 30, 30A, 30B in mounting plates 20 thatsupport blade holder rod 112 are preferably of ultra-high 65

molecular weight polyethylene (UHMW-PE) or other food-grade material, e.g., FDA/USDA food-grade material gen-

erally accepted for use in food processing and manufactur-ing. For other applications, other materials, such as stainlesssteel, steel, aluminum, composites, nylon, Teflon, otherplastics and the like may be utilized as appropriate and

5 convenient.FIG. 21 is an end view cross-section schematic diagram

of an alternative blade holder in accordance with the inven-tion. Occasionally, certain applications require scraperblades that are not easily configured as a snap-on design, orit may be desired that the scraper blade be attached to theblade holder differently. Examples of this include, forexample, metallic blades (e.g. , blades of stainless steel,aluminum, tungsten carbide), composite blades (constructedfrom a combination of metals and elastomeric/plastics), orcustom blades of various shapes and sizes. An alternativescraper blade 1120 has a geometry of an easily fabricated,customary scraper blade similar to what was described in thebackground section hereof and is shown to exemplify theapplicability of certain aspects of the invent ive scrapingblade arrangement with conventional blades. As describedearlier, the preferred shape of blade holder 110" is a rod 112"and a longitudinal through slot 1110 is machined in rod 112"to receive the body of scraper blade 1120. A through slot1110 is desired for ease of cleaning, hdwever, in certaincases, a blind slot may provide sufficient support to blade1120. Blade 1120 is held in blade holder 110" by one or moredetent pins 1130 that are diametrically inserted through rod112" transversely to slot 1110, passing through matchingholes in body 1130 of the scraper blade 1120.

While the present invention has been described in termsof the foregoing exemplary embodiments, variations withinthe scope and spirit of the present invention as defined by theclaims following will be apparent to those skilled in the art.For example, the scraping system 100 of the invention maybe employed as a primary scraper bearing against conveyorbelt 12 where it passes over head pul ley 14 of a conveyorsystem and/or as a secondary scraper bearing against the

unloaded conveyor belt 12 as it travels from head pulley 12to a tail pulley (not shown). Such secondary scraper may benear a return idler or not, as is desired, and may be in an"aggressive orientation" with blade edge 122 closer to headpulley 14 than is blade holder rod 112 or in a "passiveorientation" with blade edge 122 farther from head pulley 12than is blade holder rod 112.

Moreover, the invention can also be utilized to directlycontact conveyor belt 12 in an approximately longitudinal orin an angled fashion (each also considered to be "transverse"to the belt) to facilitate the directing, divert ing, guiding,and/or shaping of product as it is carried along by belt 12.For example, FIG. 22 is a schematic diagram of an arrange-ment in which scraping apparatus 100 and scraper blade 120'thereof are inverted and positioned above and at an angle(e.g., between 30° and 60°) with respect to conveyor belt 12to bear against bel t 12 under tension from tensioner 200.Blade 120' so placed may extend across the entire width ofbelt 12 to divert material carried by belt 12 off the edgethereof, or may extend across a portion of the width of belt12 to move material toward one side thereof, thereby toserve as a diverter or plow for all or part of the materialcarried by belt 12.

Although scraper assembly 100 is illustrated in relation toa conveyor 12, it may be utilized otherwise. One or morerods, bars or tubes of like length may be positioned betweenmounting plates 20 with their ends secured thereto byfasteners passing through holes 22 and/or 24 of mountingplates 20. Such rods, bars or tubes hold mounting plates 20and the other elements of scraping apparatus 100 in the



23US 7,083,040 B2

24proper spatial relationship absent a conveyor 12 or itssupport structure 16, and a short section of belt spanning tworods may be utilized to hold blade 120 in position. This maybe desirable, e.g., for demonstrating and/or testing operationof, and/or shipping, an assembled apparatus, although ship-ping in a disassembled state is also satisfactory.

Although half-can housing 250 is preferably about a halfcylinder, it need not be cylindrical but may be of otherconvenient and preferably arcuate shape. Although collars220, 230 may be referred to as a collar or as a flange, and 10

although they are preferably separate elements of tensioner200, at least inner col lar may be provided by a cylindricalflange on rod 112, as may be formed by turning, machining,spinning or other forming operation. Further, although col-lars 220, 230 are preferably in the shape of a cylindrical disk, 15

other shapes may also be utilized.What is claimed is:1. A torsional tensioner for tensioning a member com-

prising:a mounting plate having a hole therethrough adapted for 20

rotatably receiving the member;an arcuate housing affixed to and extending from said

mounting plate and being arcuate about an axis inter-secting said mounting plate proximate the hole therein,said arcuate housing having a circumferential slot 25

therein,an outer collar spaced away from said mounting plate and

having an arcuate edge complementary to the arcuatehousing, said outer collar being rotatable with respectto said arcuate housing about an axis substantiallyintersecting the hole in said mounting plate;

a clamp for fixing the outer collar rotatably with respectto said arcuate housing within a continuous range ofangular positions;

an inner collar rotatably disposed between said outer 35

collar and said mounting plate, said inner collar havinga through hole adapted for receiving the member and

being rotatable about an axis substantially intersectingthe hole in said mounting plate; and

a torsion spring coupled between said inner and outer 40

collars for urging relative rotational movement of saidinner and outer collars toward a relaxed position of saidtorsion spring,

wherein said outer collar has a threaded hole therein andwherein said clamp comprises a handle and a threadedstud extending therefrom through the circumferentialslot to engage the threaded hole in said outer collar.

2. A torsional tensioner for tensioning a member com-prising:

a mounting plate having a hole therethrough adapted for 50

rotatably receiving the member;an arcuate housing affixed to and extending from said

mounting plate and being arcuate about an axis inter-secting said mounting plate proximate the hole therein;

an outer collar spaced away from said mounting plate and 55

having an arcuate edge complementary to the arcuatehousing, said outer collar being rotatable with respectto said arcuate housing about an axis substantiallyintersecting the hole in said mounting plate;

a clamp for fixing the outer collar rotatably with respect 60

to said arcuate housing within a continuous range ofangular positions;

an inner collar rotatably disposed between said outercollar and said mounting plate, said inner collar havinga through hole adapted for receiving the member and 65

being rotatable about an axis substantially intersectingthe hole in said mounting plate; and

a torsion spring coupled between said inner and outercollars for urging relative rotational movement of saidinner and outer collars toward a relaxed position of saidtorsion spring,

wherein one of said outer collar and said clamp has athreaded hole therein and the other of said outer collarand said clamp includes a threaded stud extendingtherefrom, wherein said threaded stud engages thethreaded hole.

3. The tensioner of claim 2 wherein said arcuate housinghas a circumferential slot therein and wherein said clampengages said outer collar through the circumferential slot.

4. The tensioner of claim 3 wherein positioning saidclamp at an end of the circumferential slot corresponds tosaid torsion spring having a predetermined spring tension.

5. The tensioner of claim 3 wherein said arcuate housinghas a further slot extending from the circumferential slot toan end of the arcuate housing.

6. The tensioner of claim 5 wherein a first end of saidtorsion spring is permanently fastened to said inner collarand a second end of said torsion spring is permanentlyfastened to said outer collar, whereby said torsion spring andsaid inner and outer collars are removable as a unitarymember by moving said clamp through the further slot.

7. The tensioner of claim 5 wherein the further slotextends to an end of the arcuate housing distal said mountingplate.

S. The tensioner of claim 2 wherein said inner and outercollars each includes a hole in which is disposed a respective

30 end of said torsion spring.

9. The tensioner of claim 2 wherein one end of saidtorsion spring is permanently fastened to one of said innerand outer collars.

10. The tensioner of claim 2 wherein a first end of saidtorsion spring is permanently fastened to said inner collarand a second end of said torsion spring is permanentlyfastened to said outer collar, whereby said torsion spring andsaid inner and outer collars are removable as a unitarymember.

11. The tensioner of claim 2 wherein said mounting platehas at least one of a circular hole, a slot, a "T"-shaped slotand a combination thereof.

12. A torsional tensioner for tensioning a member com-45 prising:

a mounting plate having a hole therethrough adapted forrotatably receiving the member;

an arcuate housing affixed to and extending from saidmounting plate and being arcuate about an axis inter-secting said mounting plate proximate the hole therein;

an outer collar spaced away from said mounting plate andhaving an arcuate edge complementary to the arcuatehousing, said outer collar being rotatable with respect

to said arcuate housing about an axis substantiallyintersecting the hole in said mounting plate;

a clamp for fixing the outer collar rotatably with respectto said arcuate housing within a continuous range ofangular positions;

an inner collar rotatably disposed between said outercollar and said mounting plate, said inner collar havinga through hole adapted for receiving the member andbeing rotatable about an axis substantially intersectingthe hole in said mounting plate; and

a torsion spring coupled between said inner and outercollars for urging relative rotational movement of saidinner and outer collars toward a relaxed position of saidtorsion spring,



2 5

US 7,083,040 B226

wherein said clamp includes at least one of a clutch, ananti-vibration device, or both.

13. The tensioner of claim 12 wherein a first end of saidtorsion spring is permanently fastened to said inner collarand a second end of said torsion spring is permanentlyfastened to said outer collar, whereby said torsion spring andsaid inner and outer collars are removable as a unitarymember.

14. The tensioner of claim 12 wherein said arcuatehousing has a circumferential slot therein disposed in a 10

direction of rotation of said outer rotatable collar, andwherein said clamp engages said outer rotatable collarthrough the circumferential slot.

15. The tensioner of claim 14 wherein positioning saidclamp at an end of the circumferential slot corresponds to 15

said torsion spring having a predetermined spring tension.16. A tensioner for a scraper including a blade holder

rotatable about an axis for tensioning a scraper blade con-nected to the blade holder, said tensioner comprising:

a semi-cylindrical member above and extending in the 20

direction of the axis of said blade holder, wherein acentral axis of said semi-cyl indrical member is sub-stantially parallel to the axis of the blade holder;

a first collar disposed under said semi-cylindrical memberengaging the blade holder and rotatable therewith;

a second collar disposed under and releasably engagingsaid semi-cylindrical member, wherein said secondcollar engages said semi-cylindrical member for settinga tension and releases from said semi-cylindrical mem-ber for removal therefrom; 30

a torsional spring engaging said first and second collarsfor providing torsional tension therebetween when saidsecond collar engages said semi-cylindrical member;and

a clamp engaging said second col lar through a circum- 35

ferential slot in said semi-cylindrical member,wherein one of said second collar and said clamp has a

threaded hole therein and the other of said second collarand said clamp includes a threaded stud extending 40

therefrom, wherein said threaded stud engages thethreaded hole.

17. The tensioner of claim 16 wherein said semi-cylin-drical member has a circumferential slot therein and whereina clamp engages said second collar through the circumfer- 45

ential slot.18. The tensioner of claim 17 wherein posit ioning said

clamp at an end of the circumferential slot corresponds tosaid torsional spring having a predetermined spring tension.

19. The tensioner of claim 17 wherein said semi-cylin-drical member has a further slot extending from the circum-ferential slot to an end of the semi-cylindrical member.

20. The tensioner of claim 19 wherein a first end of said

torsional spring is permanently fastened to said first collarand a second end of said torsional spring is permanently 55

fastened to said second collar, whereby said torsional springand said first and second collars are removable as a unitarymember by moving said clamp through the further slot.

21. A tensioner for a scraper including a blade holderrotatable about an axis for tensioning a scraper blade con- 60

nected to the blade holder, said tensioner comprising:

a semi-cylindrical member above and extending in thedirection of the axis of said blade holder, wherein acentral axis of said semi-cyl indrical member is sub-stantially parallel to the axis of the blade holder;

a first collar disposed under said semi-cylindrical memberengaging the blade holder and rotatable therewith;

a second collar disposed under and releasably engagingsaid semi-cylindrical member, wherein said secondcollar engages said semi-cylindrical member for settinga tension and releases from said semi-cylindrical mem-ber for removal therefrom;

a torsional spring engaging said first and second collarsfor providing torsional tension therebetween when saidsecond collar engages said semi-cylindrical member;and

a clamp engaging said second col lar through a circum-ferential slot in said semi-cylindrical member,


22. A tensioner for a belt scraper including a blade holderrod rotatable about a rotation axis for tensioning a scraperblade disposed on the blade holder rod, said tensionercomprising:

a fixed monnting plate;

a semi-cylindrical housing attached to the mounting plateabove and extending in the direction of the rotation axisof said blade holder rod, wherein a central axis of said

semi-cylindrical housing is substantially parallel to therotat ion axis of the blade holder rod;

a first rotatable collar disposed under said semi-cylindri-cal housing, wherein the blade holder rod engages saidfirst rotatable collar to be rotatable therewith about therotation axis;

a second rotatable collar disposed under and releasablyengaging said semi-cylindrical housing, wherein saidsecond rotatable collar engages said semi-cylindricalhousing for setting a tension and releases from saidsemi-cylindrical housing for removal therefrom;

a torsional spring disposed under said semi-cylindricalhousing, said torsional spring having first and secondends engaging said first rotatable collar and said secondrotatable collar, respectively, for providing torsional

tension therebetween when said second rotatable collarengages said semi-cylindrical housing; and

a clamp engaging said second rotatable collar through acircumferential slot in said semi-cylindrical housing,


23. The tensioner of claim 22 wherein said semi-cyl in-drical housing has a circumferential slot therein and whereina clamp engages said second rotatable collar through thecircumferential slot.

24. The tensioner of claim 23 wherein posi tioning said50 clamp at an end of the circumferent ial slot corresponds to

said torsional spring having a predetermined spring tension.

25. The tensioner of claim 23 wherein said semi-cyl in-drical housing has a further slot extending from the circum-

ferential slot to an end of the semi-cylindrical housing.26. The tensioner of claim 25 wherein a fi rs t end of said

torsional spring is permanently fastened to said first rotat-able collar and a second end of said torsional spring ispermanently fastened to said second rotatable collar,whereby said torsional spring and said first and secondrotatable collars are removable as a nnitary member bymoving said clamp through the further slot.

27. The tensioner of claim 22 wherein a fi rs t end of saidtorsional spring is permanently fastened to said first rotat-able collar and a second end of said torsional spring is

65 permanently fastened to said second rotatable collar,whereby said torsional spring and said first and secondrotatable collars are removable as a nnitary member.

25



27US 7,083,040 B2

2828. A tensioner comprising:a unitary tensioning assembly including:

a blade holder rod rotatable about a rotation axis;a first rotatable collar affixed to said blade holder rod

and rotatable therewith about the rotation axis;a second rotatable collar spaced apart from said first

rotatable collar in a direction along the rotation axis;and

a torsional spring extending in the direction along therotation axis between said first and second rotatable 10

collars, said torsional spring having first and secondends affixed to said first rotatable collar and to saidsecond rotatable collar, respectively, for providingtorsional tension therebetween when said first rotat-able collar is rotated relative to said second rotatable 15

collar; anda mount for said unitary tensioning assembly including:

a fixed arcuate housing disposed above at least the firstand second rotatable collars of said unitary tension-ing assembly and being arcuate in the direction about 20

the rotation axis and said first and second rotatablecollars, said fixed arcuate housing having a circum-

ferential slot therein disposed in a direction of rota-tion of said second rotatable collar,

whereby said fixed arcuate housing is in a position to 25

shield at least part of said unitary tensioning memberfrom falling debris; and

an engaging device including a clamp for releasablyengaging said second rotatable collar and said fixedarcuate housing through the circumferential slot in 30

said fixed arcuate housing,wherein said arcuate housing has a further slot extend-

ing from the circumferential slot to an end of thearcuate housing, whereby said clamp may beremoved from said circumferential slot via said 35

further slot.29. The tensioner of claim 28 wherein a first end of said

torsional spring is permanently fastened to said first rotat-able collar and a second end of said torsional spring ispermanently fastened to said second rotatable collar,whereby said torsional spring and said first and secondrotatable collars are removable as a unitary member bymoving said clamp through the further slot.

30. A tensioner comprising:

a unitary tensioning assembly including:

a blade holder rod rotatable about a rotation axis;

a first rotatable collar affixed to said blade holder rodand rotatable therewith about the rotation axis;

a second rotatable collar spaced apart from said first

rotatable collar in a direction along the rotation axis;and

a torsional spring extending in the direction along therotation axis between said first and second rotatablecollars, said torsional spring having first and secondends affixed to said first rotatable collar and to saidsecond rotatable collar, respectively, for providingtorsional tension therebetween when said first rotat-able collar is rotated relative to said second rotatablecollar; and

a mount for said unitary tensioning assembly including:

a fixed arcuate housing disposed above at least the firstand second rotatable collars of said unitary tension-ing assembly and being arcuate in the direction aboutthe rotation axis and said first and second rotatable

collars, said fixed arcuate housing having a circum-ferential slot therein disposed in a direction of rota-tion of said second rotatable collar,

whereby said fixed arcuate housing is in a posi tion toshield at least part of said unitary tensioning memberfrom falling debris; and

an engaging device including a clamp for releasablyengaging said second rotatable collar and said fixedarcuate housing through the circumferential slot insaid fixed arcuate housing,


31. The tensioner of claim 30 wherein a first end of saidtorsional spring is permanently fastened to said first rotat-able collar and a second end of said torsional spring ispermanently fastened to said second rotatable collar,

40 whereby said torsional spring and said first and secondrotatable collars are removable as a unitary member.

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7083040 Tensioner as for a Belt Cleaner

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Transcript of 7083040 Tensioner as for a Belt Cleaner